Control and regulation of actuators of a robot by taking into consideration ambient contacts

Abstract

A method and device for the control and regulation of actuators of a robot, taking environmental contacts into consideration, wherein the robot comprises at least two parts, which are connected by an articulated joint drivable by an actuator. The method comprises: by way of a sensor system, ascertaining and storing a time-dependent variable, as a function of the time, of one or more external contact forces and/or of one or more external moments on the parts, providing a condition for the variable, classifying the feature vector based on predefined categories, which each indicate a contact type between one of the parts or the articulated joint and an object in a surrounding environment, which are each imparted by corresponding external contact forces and/or external contact moments, to generate a classification result, and open-loop and/or closed-loop control of the actuator as a function of the classification result.

The invention claimed is: 
     
       1. A method for the control and regulation of actuators of a robot, taking environmental contacts into consideration, wherein the robot comprises at least two parts, which are connected by way of an articulated joint drivable by an actuator, comprising the following steps:
 by way of a sensor system, ascertaining and storing a time-dependent one-dimensional or multidimensional variable G(t) which can be used to describe an action, as a function of time, of one or more external contact forces F ext  and/or of one or more external moments M ext  on the at least two parts; 
 providing a condition B for the variable G(t); 
 provided that the condition B is not satisfied by G(t) at a time to, a feature vector {right arrow over (M)} {umlaut over (M)}  (G(t)) is ascertained for the variable G(t) in a time interval T=[t a , t e ], where t a =start of the time interval, t e =end of the time interval, t 0 ∈T and to <t e , the feature vector {right arrow over (M)}(G(t)) comprising the following components:
 a median or mean value of G(t) in the time interval T; 
 a minimum and a maximum of G(t) in the time interval T; 
 a deviation of G(t) from the median or from the mean value in the time interval T; 
 a signal width of G(t) in the time interval T; 
 a frequency spectrum of G(t) in the time interval T; and 
 one or more characteristic frequencies of the frequency spectrum, 
 
 classifying the feature vector {right arrow over (M)} {umlaut over (M)} (G(t)) based on predefined categories, which each indicate a contact type between one of the at least two parts or the articulated joint and an object in a surrounding environment, which are each imparted by corresponding external contact forces F ext  and/or external contact moments M ext , to generate a classification result KE; and 
 open-loop and/or closed-loop control of the actuator for times t>t 0  as a function of the classification result KE. 
 
     
     
       2. The method according to  claim 1 , wherein the feature vector {right arrow over (M)}(G(t)) {umlaut over (M)}  additionally comprises the following components:
 Shannon entropy or Shannon entropy distribution of G(t) in the time interval T; and/or 
 a Hjorth parameter of G(t) in the time interval T; and/or 
 one or more energy parameters of G(t) in the time interval T; and/or 
 one or more autocorrelation parameters of G(t) in the time interval T; and/or 
 a skewness parameter of G(t) in the time interval T; and/or 
 one or more spectral phase parameters of G(t) in the time interval T; and/or 
 one or more spectral amplitude parameters of G(t) in the time interval T. 
 
     
     
       3. The method according to  claim 1 , wherein the start t a  of the time interval T and the end t e  of the time interval T are time-dependent: t a =t a =t a (t) and t e =t e (t), or the end t e  of the time interval T is time-dependent: t e =t e (t). 
     
     
       4. The method according to  claim 1 , wherein the robot comprises multiple parts, which are connected by way of a plurality of articulated joints drivable by an actuator. 
     
     
       5. The method according to  claim 1 , wherein the variable G(t) indicates one or more forces and/or one or more torques and/or one or more mechanical stresses and/or one or more pressures. 
     
     
       6. The method according to  claim 1 , wherein the sensor system comprises at least one sensor, which is arranged on one of the at least two parts and comprises sensor elements arranged in a planar manner for position-sensitive detection of external forces F ext  relative to the part, the variable G(t) being ascertained based on the detected external forces F ext . 
     
     
       7. The method according to  claim 1 , wherein the sensor system comprises a torque sensor and/or force sensor and/or acceleration sensor connected to one of the articulated joints for detecting a torque engaging on the articulated joint and/or a force engaging on the articulated joint and/or an acceleration engaging on the articulated joint. 
     
     
       8. The method according to  claim 1 , wherein the variable G(t) is ascertained in each case for one or more of the at least two parts and/or for one or more articulated joints. 
     
     
       9. The method according to  claim 1 , wherein, as a function of the generated classification result KE, open-loop and/or closed-loop control of the actuator takes place in such a way that a movement of the parts is stopped, slowed, accelerated, or a movement in the opposite direction is initiated. 
     
     
       10. A device for the control and regulation of actuators of a robot, taking environmental contacts into consideration, wherein the robot comprises at least two parts, which are connected by way of an articulated joint drivable by an actuator, comprising:
 a sensor system for ascertaining and storing a time-dependent variable G(t) which can be used to describe an action, as a function of time, of one or more external contact forces F ext  and/or of one or more external moments M ext  on the at least two parts; 
 an interface for providing a condition B for the variable G(t); 
 an evaluation unit, which is designed and configured in such a way that, provided that the condition B is not satisfied by G(t) at a time t 0 , a feature vector {right arrow over (M)}(G(t)) {umlaut over (M)}  is ascertained for the variable G(t) in a time interval T=[t a , t e ], where t a =start of the time interval, t e =end of the time interval, t 0 ∈T and t 0 <t e , the feature vector {right arrow over (M)}(G(t)) comprising the following components:
 a median or mean value of G(t) in the time interval T; 
 a minimum and a maximum of G(t) in the time interval T; 
 a deviation of G(t) from the median or from the mean value in the time interval T; 
 a signal width of G(t) in the time interval T; 
 a frequency spectrum of G(t) in the time interval T; and 
 one or more characteristic frequencies of the frequency spectrum, 
 
 a classification unit for classifying the feature vector {right arrow over (M)}(G(t)) {umlaut over (M)}  based on predefined categories, which each indicate a contact type between the at least two parts and an object in a surrounding environment, which are each imparted by corresponding external contact forces F ext  and/or external contact moments M ext , to generate a classification result KE; and 
 a unit for open-loop and/or closed-loop control of the actuator as a function of the classification result KE. 
 
     
     
       11. The device according to  claim 10 , wherein the feature vector {right arrow over (M)}(G(t)) {umlaut over (M)}  ascertained by the evaluation unit additionally comprises the following components:
 Shannon entropy or Shannon entropy distribution of G(t) in the time interval T; and/or 
 a Hjorth parameter of G(t) in the time interval T; and/or 
 one or more energy parameters of G(t) in the time interval T; and/or 
 one or more autocorrelation parameters of G(t) in the time interval T; and/or 
 a skewness parameter of G(t) in the time interval T; and/or 
 one or more spectral phase parameters of G(t) in the time interval T; and/or 
 one or more spectral amplitude parameters of G(t) in the time interval T. 
 
     
     
       12. The device according to  claim 10 , wherein the start, t a , of the time interval T and the end, t e , of the time interval T are time-dependent: t a =t a (t) and t e =t e (t), or the end t e  of the time interval T is time-dependent: t e =t e (t). 
     
     
       13. The device according to  claim 10 , wherein the robot comprises multiple parts which are connected by way of a plurality of articulated joints drivable by an actuator. 
     
     
       14. The device according to  claim 10 , wherein the variable G(t) indicates one or more forces and/or one or more torques and/or one or more mechanical stresses and/or one or more pressures. 
     
     
       15. The device according to  claim 10 , wherein the sensor system comprises at least one sensor, which is arranged on one of the at least two parts and comprises sensor elements arranged in a planar manner for position-sensitive detection of external forces F ext  relative to the part, the variable G(t) being ascertained based on the detected external forces F ext . 
     
     
       16. The device according to  claim 10 , wherein the sensor system comprises a torque sensor and/or force sensor and/or acceleration sensor connected to one of the articulated joints for detecting a torque engaging on the articulated joint and/or a force engaging on the articulated joint and/or an acceleration engaging on the articulated joint. 
     
     
       17. The device according to  claim 10 , wherein the variable G(t) is ascertained in each case for one or more of the parts and/or for one or more articulated joints. 
     
     
       18. The device according to  claim 10 , wherein, as a function of the ascertained classification result KE, open-loop and/or closed-loop control of the actuator takes place in such a way that a movement of the parts is stopped, slowed, accelerated, or a movement in the opposite direction is initiated.